Beef Pot Pie (can use the refrigerated pie crusts or bisquik to make it a "fast" leftover meal)...
Chunky Chilli (the meat chunks in place of ground beef is a nice change of pace)...
and like PP said, soup (I use my hamburger soup recipe but throw in the leftover roast instead of browning the ground beef.)

Shred the meat and make quesadillas with it - I like to use leftover pot roast, whatever kind of cheese we have, and green chilies if we have them. Yum!

Jen

I have a similar suggestion- we use leftover meat for enchilada casserole- I put the meat in the food processor and grind it up, then mix with refried beans; add tomatoes, cheese, etc, then wrap in tortillas and put in a casserole. Then I make a white cheese sauce that has cumin and groud red pepper in it, and pour over the top. YUMMY! Oh, I add spinach to the enchiladas too. Great way to get veggies into everyone.